* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
body {
  font-family: Microsoft YaHei;
  font-size: 12px;
  line-height: 1.5;
  background-color: #373535;
  color: #fff;
}
.time-line ul {
  padding-bottom: 24px;
}
.time-line ul li {
  list-style: none;
  position: relative;
  padding-top: 50px;
  width: 6px;
  margin: 0 auto;
  background-color: #fff;
}
.time-line ul li::after {
  content: "";
  position: absolute;
  left: 50%;
  bottom: 0;
  transform: translateX(-50%);
  width: 30px;
  height: 30px;
  background-color: #fff;
  border-radius: 50%;
}
.time-line ul li.in-view::after {
  background-color: #B01A20;
  transition: background-color 0.5s ease-in-out;
}
.time-line ul li div {
  position: relative;
  width: 400px;
  padding: 15px;
  background-color: #B01A20;
  bottom: 0;
  visibility: hidden;
  opacity: 0;
  transition: all 0.5s ease-in-out;
}
.time-line ul li div::before {
  content: "";
  position: absolute;
  bottom: 7px;
  width: 0;
  height: 0;
  border-style: solid;
}
.time-line ul li:nth-child(odd) div {
  left: 45px;
  transform: translateX(200px);
}
.time-line ul li:nth-child(odd) div::before {
  left: -15px;
  border-width: 8px 16px 8px 0;
  border-color: transparent #B01A20 transparent transparent;
}
.time-line ul li:nth-child(even) div {
  left: -439px;
  transform: translateX(-200px);
}
.time-line ul li:nth-child(even) div::before {
  right: -15px;
  border-width: 8px 0 8px 16px;
  border-color: transparent transparent transparent #B01A20;
}
.time-line ul li.in-view div {
  transform: none;
  visibility: visible;
  opacity: 1;
}
@media screen and (max-width: 1000px) {
  .time-line ul li div {
    width: 250px;
  }
  .time-line ul li:nth-child(even) div {
    left: -289px;
  }
}
@media screen and (max-width: 675px) {
  .time-line ul li {
    margin-left: 48px;
  }
  .time-line ul li:nth-child(even) div,
  .time-line ul li:nth-child(odd) div {
    left: 45px;
  }
  .time-line ul li:nth-child(even) div::before,
  .time-line ul li:nth-child(odd) div::before {
    left: -15px;
    border-width: 8px 16px 8px 0;
    border-color: transparent #B01A20 transparent transparent;
  }
}
